Max load factor on head.
Certification Specifications for Small rotorcraft - CS 27
CS 27 337 limit manoeuvring load factor = +3.5G to - 1G with a built in safety factor of 1.5.
Obviously could be greater but then heavier and more costly.
When you know that the blade loading at 1G on the 300CBi is 77.29 lb/ square ft then 3.5 x77.29 = 231.87 lb/square ft is asking a lot of the blades and their attachments. Fortunately this can only be maintained for a very short time due to the lack of power.
However,think of your mate who will fly it in a few weeks time!